Hydrogen Bonding Flashcards
Hydrogen bonds only occur between certain elements including oxygen, nitrogen and fluorine, what are these resulting compounds commonly referred to as?
They are often referred to as hydrides, compounds of hydrogen and one other element
Define hydrogen bonds
3
Hydrogen bonds are particular types of dipole-dipole attractions between molecules in which hydrogen atoms are bonded to nitrogen, oxygen or fluorine
The hydrogen atom carries a partial positive charge and is attracted to the electronegative atom in another molecule
Thus, the hydrogen bond acts as a bridge between two electronegative atoms in separate molecules
Which are stronger hydrogen bonds or dipole-dipole bonds?
Hydrogen bonds
How do hydrogen bonds arise?
They arise when an atom of hydrogen is bonded to an atom of fluorine or oxygen or nitrogen i.e. with the three most electronegative elements in the Periodic Table
List the top three most electronegative elements in the Periodic table
Fluorine
Oxygen
Nitrogen
How are hydrogen bonds drawn?
They are shown as dotted lines
Which are stronger hydrogen bonds or covalent bonds?
Covalent bonds
How strong are hydrogen bonds compared to covalent bonds?
Hydrogen bonds are about 10% as strong as covalent bonds
Even though hydrogen bonds are much weaker than covalent bonds they have a significant role, why is this?
This is because there are so many hydrogen bonds
Why is the hydrogen bonding in H2O stronger than NH3?
Since the electronegativity of oxygen is higher than that of nitrogen
What would happen to water is hydrogen bonding did not exist?
If hydrogen bonding did not exist in water, then water would be a gas at room temperature and life, as we know it, could not exist on Earth
Give a synthetic use of hydrogen bonding.
Kevlar - synthetic clothing
Describe Kevlar.
Fire resistant, extremely strong and flexible
Give a natural use of hydrogen bonding.
The proteins in wool can form hydrogen bonds which allows wool to absorb water
What affect does hydrogen bonding have on water?
Hydrogen bonding gives water its high surface tension as the attraction of the water molecules on the surface of water gives rise to a type of ‘skin’
